Model Output Discussions 12z 01/09/2016

[Frosty.]

The Ecm 12z ens mean, just like the op shows very pleasant anticyclonic weather on the way with unseasonable warmth across the south of the uk with the peak occuring this weekend but then a gradual transition to colder Nly winds next week with pressure leaking away and height rises to the w / nw...our first cold shot will arrive from the north during next week if this verifies.

[Gael_Force]

55 minutes ago, Essex snowman said:

After fergieweathers update seem a let down for us coldies well at least for next couple of weeks :-(

Posting such as this should face an automatic ban until winter is over! Have you forgotten, last winter, such silly nonsense led to the cessation of useful updates from a very knowledgeable source.

Edited October 25, 2016 by Gael_Force

[knocker]

 

[bluearmy]

14 minutes ago, fergieweather said:

Not at all. 12z EC EPS continues to show a conspicuous descent to (possibly fairly marked) below average temperatures 1st week of Nov. Extended EPS clusters beyond T+240 offer various colder (mostly cyclonic) possibilities in the mix. Nothing can yet be discounted.

note a parallel ECM op and 46 day ens available behind various paywalls.  I believe these are due to come on stream around 23/11

fwiw, the para 00z run was closer to the 12z op in its latter stages. There is little sign that there is anything in the pipeline for first half November other than has been well advertised over the past week or so. HLB and chilly to cold at times. 

[Walsall Wood Snow]

As long as the building blocks remain in our favour, I see no need for despondency and we shouldn't feel too much in a rush to get our first cold spell. After all the longer it takes to get one the greater its potential potency. After all November can deliver cold but it's not Winter. I'd rather have a slow and gradual build up ready for a locked in attack during Winter proper than a quick fix. It's the trend that matters now more than anything.

[Captain Shortwave]

      

Not much else to say on the ECM ens, the Euro ridge declines with below normal heights developing over northern and central Europe with a ridge in the Atlantic, so an increasingly cool or even cold picture as we move through next week.

Same goes for the GFS ens

      

So still on course for a colder spell at the start of November, though delayed by a day or so due to the complex handling of the trough in the Atlantic, how much of a cold pool left to our south west is unknown but the longwave pattern looks fairly set as we move into the last month of Autumn. The first widespread night time frosts look likely next week, not going to suggest anything else as I suspect wintry precipitation will be restricted to high ground but a small taste of what is hopefully to come during the coming winter months.

Edited October 25, 2016 by Captain Shortwave

[bryan629]

14 minutes ago, bluearmy said:

note a parallel ECM op and 46 day ens available behind various paywalls.  I believe these are due to come on stream around 23/11

fwiw, the para 00z run was closer to the 12z op in its latter stages. There is little sign that there is anything in the pipeline for first half November other than has been well advertised over the past week or so. HLB and chilly to cold at times. 

Hi BA, 

Ryan Maue advertised this on twitter last sunday.. the ECM parallel , which isnt pay walled.. it doesnt have 850s or NH profiles though. 

Usefull non the less http://models.weatherbell.com/ecmwf/ecmwf_parallel.php  although i would be a bit wary of sharing the charts.. maybe a look at the small print at the bottom right hand corner , just to inform you 

Edited October 25, 2016 by bryan629

[Man With Beard]

This is a good one for getting colder air in:

Blocking all over the pole, having some influence on our side od the Atlantic, and lower heights towards Scandi.

Now this definitely is not a million miles away from bringing something quite cold to the UK.

[lorenzo]

We are at the stage where aligned to the projected Scandi dissolution the NH profile retains a blocked template - really is fascinating. @Tamara nailed a brilliant nuance of the output over the weekend talking about do the oceans and atmosphere connect. In this case no! Confused AAM picture, atmosphere wanting to roll downhill but somewhat not letting go..

Super Nino Aleutian Low vs declining Oceanic phase in Pacific from the kettle boiling with Nino over last season and threatening El Nada or La Nina - never in harmony.

One wonders if there was such a winter with so many wildcards...

Decline of Super Nino - it was one of 'the' super strong events - all but qualified by QBO interrupted for first time since 1958, this either uber confirmed the ENSO strat pathway by destroying the QBO completely or undermined it - not made up my mind !

Other considerations just now in the modelling are - 

Top 5 event for October Stratospheric Heat Flux

Lowest Sea Ice and minimum value recorded across last week.

Lowest projected u wind modelling out with historic record.

NB this has eased off considerably since mid last week where reversal visible through a few ensemble members

Realtime considerable decline in sunspot activity vs declining geomagnetic flux

OPI/SAI temptations given the monstrous gains in Snow Advance - can this analog come back on line 

All these are drivers of atmospheric patterns, feed backs and pre cursors one could hope to use to deliver some premise of winter ahead.

At present it is a brave call for those releasing any kind of winter ahead look given current variables - more trust in one mode than the other perhaps, yet some forecasts already out and a few are imminent, point of this post is to highlight the navigation required within the variation.

For now I think patience is the key - it is easy to be drawn to the polar blocking profile the lack of 'oomph' in the jet, the lack of thermal gradient brought about by a perfect recipe for wave breaks and blocks.  ( depleted Arctic profile compared to our usual ugly jet shenanigans).

Will this last across the season, recycle, repeat or imprint.

Does the Nino lag in the atmosphere carry Aleutian trigger low for stratospheric wave driving further into winter, will it reach a critical point that truly identifies the SSW trigger zone, will the QBO reinvigorate, will geomag decline more quickly than expected. All tricky calls.

What is supported in the immediacy in the modelling can quickly shift  -we have another 10 days of what ifs - including, imagine this were deep in the heart of winter - it is easy to be fantastical around what you want to see evolve. 

The caveats are clear - declining solar predicates the atmosphere to a weakly positive NAO for DJF given EP forcing and long set analogs +0.2 or so weight to NAO positive across DJF and also  we are heading into vortex peak cooling and intensification season.

Whilst excellent studies pinpoint Sea Ice, Vortex Strength, Geomagnetic Influence and Pacific mode - I think the one determining factor for our local remaains the insular mode of the vortex itself.

We are the closest to top 4 or 5 events for disturbance right now - from a roller coaster view let's hope the blocking outlook continues to imprint and we have real weakness across all levels going into November - any nudges / anomalies thereafter could make trop modelling fun!

[Ice Day]

3 minutes ago, lorenzo said:

One wonders if there was such a winter with so many wildcards...

We are the closest to top 4 or 5 events for disturbance right now - from a roller coaster view let's hope the blocking outlook continues to imprint and we have real weakness across all levels going into November - any nudges / anomalies thereafter could make trop modelling fun!

Bloody hell Lorenzo, that is a brilliant post; so not to jam up the thread, I've just copied a couple of your points.  This tells the tale perfectly of where we are at......virtually uncharted territory.  Any assertions of where winter 16/17 is going is going to be a brave call.  What I would say is that this is the best October model watching in my 10 years on NW.  Right, time for the pub run!

[bluearmy]

13 minutes ago, bryan629 said:

Hi BA, 

Ryan Maue advertised this on twitter last sunday.. the ECM parallel , which isnt pay walled.. it doesnt have 850s or NH profiles though. 

Usefull non the less http://models.weatherbell.com/ecmwf/ecmwf_parallel.php  although i would be a bit wary of sharing the charts.. maybe a look at the small print at the bottom right hand corner , just to inform you 

Are you sure it's in the public domain?  I mean you linked to it so assume it's ok ?  Not sure what you meant by being wary about sharing the charts and then posting a link!! 

Anyway, it the parallel op is freely available, perhaps sylvain can stick it on meteociel as he often does pre implementation.

[bryan629]

1 minute ago, bluearmy said:

Are you sure it's in the public domain?  I mean you linked to it so assume it's ok ?  Not sure what you meant by being wary about sharing the charts and then posting a link!! 

Anyway, it the parallel op is freely available, perhaps sylvain can stick it on meteociel as he often does pre implementation.

yes its public..

 

[SMU]

Awsome vertical advection on the 18z

gonna be a hummdinger!!!!

[lorenzo]

Not just the VA - ruler line vertical - that Aleutian low is a pro-boxer getting savage on everything - absolute beaut of an anomaly!

[Frosty.]

The Gfs 18z shows a pleasantly warm anticyclonic spell which lasts into early next week..really nice temps across the southern half of the uk, exceptional on the cusp of November!

Edited October 25, 2016 by Frosty.

[Mucka]

JMA extended out and it is cold and blocked.

That would be an interesting bonfire night.

Edited October 25, 2016 by Mucka

[Frosty.]

Even by next midweek the Gfs 18z still looks fine with above average temps further south. A humdinger indeed!

[feb1991blizzard]

4 minutes ago, Mucka said:

JMA extended out and it is cold and blocked.

That would be an interesting bonfire night.

Yes, that's probably the best op run of the season so far wrt getting cold in quickly, GFS late on also bringing cold from NE nearer than the 12z  although  different to 12z.

[Barry12]

3 minutes ago, Frosty. said:

Even by next midweek the Gfs 18z still looks fine with above average temps further south. A humdinger indeed!

Can't wait frosty! It could even reach the dizzy heights of 13C in our neck of the woods, I think I'll get my BBQ out!

The GFS have average temperatures throughout, but still plenty of blocking, massive differences at day 7, so plenty more changes to come.

[Mark Neal.]

A messy evoulution as far as next week goes after the high over us and mild temperatures stall. Thereafter The low from NW Atlantic takes an age to move across the UK, finally drops SE. Easterly follows and some colder air to tap into from NE not far away.. how lovely! Very messy but interesting from the pub run.  

 

Edited October 25, 2016 by Mark N

[bobbydog]

11 minutes ago, Frosty. said:

Even by next midweek the Gfs 18z still looks fine with above average temps further south. A humdinger indeed!

These aren't the charts we are looking for....

[fergieweather]

18z GFS going off on a November journey into a coldie's Nirvana. Did one of you lot hack into NCEP's dynamical core coding? ;-)

[bobbydog]

2 minutes ago, fergieweather said:

18z GFS going off on a November journey into a coldie's Nirvana. Did one of you lot hack into NCEP's dynamical core coding? ;-)

Jedi mind trick Ian..... 

[Mark Neal.]

The low eventually moves into France & low countries. Also by this time the very cold air to NE floods into the low countries. not that far away! Got to love the pub run. 

 

Edited October 25, 2016 by Mark N

[Mark Neal.]

Pub run ends with slack high to North of the UK. Then low in Atlantic tries to come in but slides into Channel. Left with easterly oncemore with cold air over the country. Easterly flow in Scotland and far north East sees the cold pool to NE introduce some very cold uppers and probably some wintry precip for those who are far enough north in the UK. 18Z GFS pulled of a pub run special lol

  

Edited October 25, 2016 by Mark N